So this is very similar to what we saw i n terms of sigma orbitals and pi orbitals.

这和我们在sigma轨道,和π轨道中看到的很像。

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But in sigma orbitals, you have no nodal planes along the bond axis, so if we had a nodal plane here, we'd see an area where the wave function was equal to zero.

但在sigma轨道里，沿着轴向是没有节点平面的，如果我们有个节点，我们就会看到某个地方波函数等于0。

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First of all, this is the two s orbitals in hydrogen, 1s plus 1s smearing to give us this sigma molecular orbital.

首先，这是氢气中的两个s轨道，1s与1s轨道重叠,产生sigma分子轨道。

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But keep in mind sigma orbitals have no nodal planes along the bond axis.

但记住sigma轨道沿着,键轴方向是没有节点的。

麻省理工公开课 - 化学原理课程节选

So that's why these are pi orbitals instead of sigma orbitals.

这就是为什么它们是π轨道而不是sigma轨道。

麻省理工公开课 - 化学原理课程节选

And a sigma bond forms any time you have two orbitals coming together and interacting on that internuclear axis.

当你把两个轨道合在一起,并在核间轴上有相互作用时,就形成了sigma键。

麻省理工公开课 - 化学原理课程节选

Any time two orbitals come straight on together in that internuclear axis, you're going to have a sigma bond.

任何时候两个轨道,在核间轴上直接到一起，你就能得到sigma键。

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Again, we're going to take the linear combination of those p atomic orbitals and make what are called pi or some more sigma molecular orbitals.

同样的，我们需要得到,原子p轨道的线性组合,然后组成我们所说的,π分子轨道或者sigma分子轨道。

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So z equals 7 -- this is the cut-off where, in fact, the sigma orbital is going to be higher in energy than the pi 2 p orbitals.

所以z等于7-这是分界点，实际上，sigma轨道能量,要比π2p轨道高。

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What about this second bond here sigma where we're going to have interaction of 2 p orbitals, is that sigma or pi?

那2p轨道相互作用的第二个键呢,它是，还是π？

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Another thing I want to point out about every sigma orbital that you see, and it will make more sense when we contrast it with pi orbitals later.

另外一个我要指出的事情就是,关于每个sigma轨道你能看到,当我们把它和π轨道对比的时候会看的更清楚。

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So some p orbitals form pi molecular orbitals, and some form sigma p orbitals.

有些p轨道会形成π分子轨道，有些会形成p轨道。

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So we're going to call this the sigma 2 p x star, or if we're talking about the 2 p y orbitals we'll call this the pi 2 p x star, and the pi 2 p y star.

我们叫这个sigma2px星，或者如果我们说的是π2py轨道的话,我们叫这个2px星，这个π2py星。

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z And what you need to remember is if the z 8 is equal to eight or greater, such as oxygen being the cut-off point, this sigma 2 p orbital is actually lower in energy than the pi 2 p orbitals, the molecular orbitals.

你们要记住如果,等于或者大于，就像O是分界点，这时sigma2p轨道,比π2p轨道能量更低。

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